The invention relates to an apparatus for inserting an endless, flexible clothing in or removing such a clothing from an industrial machine in which the clothing is arranged to run in an endless loop, comprising:                a first structural unit and a second structural unit being arranged opposite to each other, said apparatus being arranged to feed the clothing between the first unit and the second unit in a clothing advancement direction essentially transversal to the run direction of the clothing in the machine.        
The invention also relates to an industrial machine comprising a flexible clothing running in an endless loop and such an apparatus for inserting the clothing in or removing the clothing from the machine. Such an industrial machine can for example be a paper web forming or processing machine.
The invention also relates to a method of inserting an endless, flexible clothing in or removing such a clothing from an industrial machine.
The invention also relates to the use of such an apparatus in an industrial machine, in which case the apparatus may be an integrated part of the machine or a separate mobile unit.
In this application the term “clothing” is understood to have a relatively wide meaning. In particular, the term “clothing” is understood to represent any type of relatively thin, flexible member that is intended to run in an endless loop in the industrial machine. For example, the clothing can be a felt, a fabric, a belt, e.g. a conveyor belt, a band or a wire. The clothing may alternatively be made of a plurality of flat elements interconnected to form a band. The clothing may be made of a polymer, a metal or a composite material. The clothing may be woven or non-woven. Typically, the clothing is used to support or transport some kind of product in the machine.
In particular, the invention relates to an apparatus for inserting or removing, i.e. mounting or demounting, an endless clothing in a web forming or web processing machine. In a web forming or processing machine, such as for example a papermaking machine, a tissue machine, a pulp processing machine or a paperboard making machine, the web is led through the machine by at least one clothing that runs in an endless loop over a plurality of support rolls suspended in a frame of the machine. The clothing can be a felt, a fabric, a belt, a band, a wire or any other type of thin, flexible member that is intended to carry, imprint or otherwise interact with the web during its travel through the machine. The clothing can be made of polymer, metal or composite material. The clothing can be wide and also relatively heavy. For example, a clothing in a web forming or web processing machine can be up to 10 to 12 m wide.
When mounting a clothing in a web forming or processing machine, it is possible to mount a clothing having two ends in the machine and to connect the ends of the clothing once the clothing has been fitted in the machine. Consequently, when such a clothing is used, a seam or a joint between the ends needs to be constructed, which is relatively time consuming. Furthermore, seams or joints may cause unacceptable markings in the web. Therefore, a clothing for use in a web forming or processing machine is usually prefabricated such that it forms an endless loop. When replacing such an endless clothing, which has to be done relatively often due to its wear, e.g. every 3 to 6 months in the case of forming wires and every 3 to 10 weeks in the case of press section felts, the new clothing must be mounted from the side of the machine, i.e. either from the drive side or from the tender side. Normally the tender side offers the most space for such an operation.
However, when using this kind of sideways or cross direction (CD) replacement method the obvious problem arises of getting the clothing through the frame structure in which the support rolls are suspended.
A known solution to this problem is to provide the vertical beams on the tender side of the frame with removable spacer blocks. When a clothing is to be replaced, a counter-lever system on the drive side of the frame is utilized to unload the vertical beams on the tender side. After unloading the vertical beams, the spacer blocks are removed and the clothing can then be replaced through the gaps thus formed in the frame structure. Although cantilevering is a robust solution, it is desirable to find an alternative since its implementation is space consuming and also cost demanding.
An alternative to cantilevering is disclosed in WO 2006/106178 A1 and WO 2008/129131 A1, where units comprising counter revolving bands and/or sliding surfaces are arranged in the vertical beams. When a clothing is to be passed through the beam, the clothing is fed into the nip between the bands or the sliding surfaces of the unit and is brought to the other side of the beam, either manually or by a rotational movement of at least one band of the unit. Another alternative to cantilevering is disclosed in EP 2 063 023 A2, where units comprising pulling devices are arranged in the vertical beams. When a clothing is to be passed through the beam, the clothing is fed in between the pulling devices, after which the clothing is locked between the pulling devices and the pulling devices pull the clothing through the beam.
Although the disclosed units do require very little space, the devices disclosed in WO 2006/106178 A1, WO 2008/129131 A1 and EP 2 063 023 A2 are relatively technically complicated and thus also expensive to fabricate. Furthermore, in the disclosed devices the clothing is brought through the beam while being loaded by the forces acting on the beam. In other words, the part of the clothing which is brought through the beam is subjected to the full weight of the beam. Consequently, the part of the clothing which is brought through the beam is simultaneously subjected to a shearing force due to the advancing movement of the band/sliding surface/pulling device, and to a normal force due to the weight of the beam. This is, however, an unfavourable loading condition which may damage the clothing.
One objective of the invention is to provide an improved method and an improved system which do not display these drawbacks. Another objective of the invention is to provide a method and a system which enable operators to replace a clothing in an industrial machine, and in particular in a web forming or processing machine, in a fast and easy manner without having to risk damaging the clothing.